Split reduction device



May 2l, l929. T. H. THOMAS SPLIT REDUCTION nEvIcE Filed June 18, 1927 l Tri .2

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PATENT oFFIcEgIL THOMAS H. THOMAS, or EDGEWooD, PENNSYLVANIA, ASsIGNon To THE 'wrSTINe-k HOUSE Am BRAKE COMPANY, or` WILMEILDING, PENNSYLVANIA, A CoRroRATIoN E PENNSYLVANIA.

SPLIT REDUCTION DEVICE.

Application led June 18,1927. Serial No.`199,675.

This' invention relates to vfiuid# pressure4 brakes vand more particularly to a locomotive brake equipment, of the type having means for automatically controlling the .applica- 5 tion of train brakes. f

In operating railway trains, it is-the usual practice for the engineer,in effectingan kapplication of the brakes, to manipulate the brake valve device in such a manner as -to first make a light brake pipe reduction, to insure the application of all brakes von the train, in such a manner, that the slack between the cars of the train will not be permitted to run in harshly. After kthe slack has thus beengatliered, the engineeragain manipulates the brake valve device to effect a heavier brake pipe reduction suflicient to produce the desired application of- Vthe brakes. Y

Ithas also heretofore been proposed vto automatically effect a- 'brake pipe'reduction in two stages, Such tha-t the linitial stage will be'sullicient to cause al gentle `gathering of the train slack and then the second stage of the brake pipe reduction is" started.

, According to my invention, I propose to'` provide 4'means adapted' to automatically effect a brake pipe reduction at two different rates, instead of in two separate stages. The initial rate of brake pipe'reduction being made at a slow rateand being adaptedto cause a gentle gathering of the train slack and then after the slack is thus gathered, the rate of vbrake pipe reduction is automatically increased to aifaster rate, which is adapted to apply the brakes with they desired force. A Y' Other objects and advantages :will/appear in the following more detailedv description of my invention.V n

In the accompanying drawing, Fig, 1 isy a diagrammatic sectional view of a kfluid .pressure brake apparatus embodying my `A`invention; and Fig. 2 a sectional view of the controlling magnet.

y As shown in the drawinv f g, the apparatus may comprise a brake valve device, an application valve device, abrake pipe' reduction control valve device anda magnet valve device. Y The brake valve deviceeomprises the usual Vrotary valve 4 contained in a valve chamber 1 and adapted to be operated by a handle 5.

Associated with the brake valve Adevice'v is the usual discharge valve mechanism *com prising an equahzing piston 6, forming, at

one side, a chamber 7, lconnected withran equalizing reservoir 8, in a manner 'herein-l after more fully" described, and at theoppo`- site side a chamber 9 connectedvtoheusual brake pipe 10, through passageand pipe 11', said piston lbeingadapted tooperate a brake pipe discharge valve. 12.

The equalizing piston device is ofthe collapsible type, the. piston 6, thereof, being looselyeonnectedwith thedischarge valve 12, so asvto permit relative ydownward movement of the equalizing pistonv after the discharge valve 12 is seated land in the ext-reine downward position of the equalizing piston, communication'is openedbetween the chainbers 7 and 9, through equalizing grooves 13, provided in the wall ot the chamber 9.' In order to vpermit movement of the equalizin'g piston 6, relative to ,the discharge valve 412, the equalizing'piston 6 isprovided with a Vprojection having a chamber, in whichlthe inner endl portionvo'f the discharge valvef12 1s loosely mounted andv containinga spring 14, adapted to yieldingly maintain the equal#A` izing piston 6 and discharge valve12 in 'their normal relativepositions, as s howninthe drawing., a -sh'oulder 15' being provided onl the inner endiportion of the dischargev'alve 12for -engaginga `corresponding shoulder movement of' the equalizingpiston.v Y

The application valve devicecomprise's a piston 33, contained in a chamber 32 and i subject to the pressurey of a spring 434 also' contained in said chamber, and a slide v alve 37 contained in La' valvev chamber 35 and adapted to be operated bythe piston 33.'

vThebrake pipe yreduction vcontr'ol'valve device comprises a diaphragm-16, forming a chamber 17.at one side, said chamberbeing connected by passage 18-to thev equalizing piston chamber 7 and by passage 19 to the equalizing'reservoir 8. VVAt the opposite side of the diaphragm 16, va chamber 20 is formed,

whichchamberr is connected 'to a yreduction limiting reservoir l21 by a passage' and pipe22.V ,m f

A valve 25 isV contained in chamber 20 and is adapted to be operated by a stem 26,'depending from thelollower'plateV 2750i the B5 Y in the-chambered projectionl to limitv upward diaphragm 16. Said valve has a luted stem, extending through a plug 24, having screwthreaded engagement in the casing, and terminating ina chamber 23, wherein a spring 28,l acting upon a thrust Washer 29, opposes the seating of said valve. Interposed between thediaphragm follower plate 27 and the lug 24 is a coil spring 30.

T ie magnet valve device comprises a cas-` ing containing a magnet and having a cl1ainber 53, connected to the :atmosphere through a passage 54 and containing a valve 55. Said valve has a lluted stem, Which extends through the casing-Wall into a Vchamber 56, said chamber being connected to the application piston chamber 32, through `passage and pipe 38. The lluted stem of the'valve is engaged in chamber 5,6, by a fluted stem 57, Which extends throughthe casing Wall into a chamber 58 and has formed at its lower end a collar 59. Aspring 60, contained in the chamber 58, engages the stem collar 59and is adapted to unseat `the valve 55.

In operation, fluid underpressure fromthe main reservoir 2 is suppliedthrough pipe and passage 3 tothe rotary valve chamber l and to feed valve device 36, Which `is adapted to supply fluid, at the reduced pressure carried in the brake pipe, to the application valve chamber 35 by Way 4of passage and pipe 40. Fluid under pressure from this valve chamber 35 then flows through port 41 vin the piston33 into the piston chamber 32 and from thence through the passage and pipe 38 to chamber 56 of the magnet valve device. t .Y i

By means of apparatus which need not here lbe described, the magnet is energized when the signal conditionis favorable `or Cir When the speed of the train is Within a predetermined speed limit. Vlith the magnet energized, the magnetfvalve` 55 is held seated against the pressure of spring 60, and the fluid in chamber 56 and application piston chamber 32 equalizes With the pressure in the application valvechamber35, so that the pressure of spring 34 then holds the application piston 33 and slide valve 37 inthe inner or release position, as shown in the drawing. Y Y

l/Vith the application valve device-.in release position, fluid 4at feed valve pressure from the valve chamber=35 `ovvs to the brake pipe 10 through passage 42, port 43 in the rotary valve 4, passage 44, equalizing piston chamber' 9'and passage 11. Fluid at feed valve pressure is also supplied to thcY equalizing reservoir 8 through port 43 in the rotary valve, by Way of passage 45,.ca.vity 46 in the slide valve 37 and passage 19 and from passage 19 to the diaphragm chamber `17 and through passage 18 to the equalizing-piston chamber 7.

With the slide valve 37 in release position, the reduction limiting reservoir 21 is vented to the atmosphere by way of passage 22, diaphram chamber 20, passage 47, cavity 48 in the slide valve 37, passage 49 and through a choke plug 50.

lVith the diaphragm chamber 20 at atmospheric pressure and the chamber 17 at the pressure in the equalizing reservoir, the diaphragm 16 is operated to hold valve 25 seated.

If the tack conditions become unfavorable, the magnet will be deenergized and the valve 55 opened, so that fluid is vented from the piston chamber 32 of the application valve device to the atmosphere through passage and pipe 38and the pressure of the fluid in the valve chamber 35 then shifts the application piston 33 and slide valve 37 to their outer position, in which position the slide valve Vlaps passage 42, thereby preventing further tloiv of fluid under pressure to the brake pipe 10.` In this position ofthe slide valve 37, cavity 48 connects the brake pipe 10 to the atmosphere, by Way of pa sages 11 and 49 and choke plug 50, so that the brake pipe pressure is permitted to gradually reduce at a rate permitted by the choke plug 50 and as a result, a gradual applicztion of the brakes is effected Further, in this position of the slide valve 37, cavity 46 connects passage 19 topassage 51, so that fluid under pressure from the equalizing reservoir 8 is permitted to flow to the chami ber 23. Sincetlie relative volume of chamber 23 is very small, no appreciable decrease in equalizing reservoir pressure is thus effected.

As the brake pipe pressure is reduced, as above described, the pressure in the chamber 9, at one side of the equalizing piston 6 of the brake valve device reduces correspond ingly, and since the equalizing reservoir pressure, effective in the equalizing piston chamber 7, is not being reduced, it acts on the piston 6 to move it toa position, Vin which the equalizing ports 13 connect the two chambers 7 and 9, so that, the pressure ol4 the fluid in the equalizing reservoir S is permitted to drop `as the brake pipe pressure is reduced.

Vhen the pressure of i'luid in the equalizing reservoir and in chamber 17 has been reduced to a degree slightly less than ther pressure of the spring 30, the diaphragm 16 will be moved, so as to unseat the valve 25 and thus Aconnect the chambers 23 and 2U. Fluid under pressure in the equalizing reservoir 8 and in the equalizing piston chamber 7, then flows to the reduction limiting reservoir 21, at a predetermined rate, conL trolled by the size of the opening through llt) duces in the equalizing` piston .chamber 7, said brake pipe pressure shifts the equalizing piston 6 upwardly, which opens thedis charge valve 12 and perinitsfluid under pressure in the bi'ake pipe 1() to flow through a port to the atmosphere at a high rate, thereby causing the train brakes to be quickly applied. f

The combined, flow area of choke lplug 5() and the discharge port controlled by the discharge valve 12, is preferably such as to permit'substantiallythe same rate of reducion in brake `pipe pressure as is obtained in effect-ing a service application of brakes, in the usual manner.

The reduction limiting reservoir 21 is eni-k ployed to limit the degree of' drop in equalizing reservoir pressure to thatnecessary for a iull service brake application'. v.lVhen the brake pipe pressure in the equalizing piston chamber 9 becomes slightly less' than the reduced `eipializing reservoir pressure lin piston chamber 7, the piston 6 operates to seat the discharge valve 12 and prevent further flow of' fluid under pressure from the brake pipe to the atmosphere.

The timerequired for effecting a degree of brake pipe reduction such that theensuing brake application willl be sufficient to gather the slack in a train, varies as the train length varies and since, according to my invention, the start of brake pipe reduction, at a faster rate, is dependent upon a predetermined drop in brake pipe pressure, said faster rate of' brake pipe reduction will automatically be started'at the desired time. In the case of leakage of fluid under pressure 'trom the brake pipe tothe atmosphere, it will `be noted, that as the degree otsaid leakage increases, it obviouslyl increases vthe rate at which the initial reduction in brakey pipe pressure is e1l'ected,'witli the result, that the brake pipe reduction at the faster` rate will be started sooner, after the start lof the .initial reduction, the period of time being proportionate to the degreey of brake. pipe leakage. 1

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is y 1. Ina fluid pressure brake, the combination with abrake pipe, of means for auto- ,end of said period of time.v

Vlength of the train, said reductions at Vdiffering rates being continuous one with the other. l y K al. In affluid pressure brake, the combination with a brake pipe, of means for reducing thcpressure of fluid in said brake pipe at n a predetermined rate, and means subject to the reduced pressure of vfluid. in said brake pipe for accelerating the rate of said reduction.

5. In a fluid presssure brake, the combination with a brake pipe, of means for reducing the. pressure of fluid in said brakepipe at a predetermined rate, and means subjectfto the reduced pressure of fluidv in said brake pipe for continuing the brake pipe reduc'- tion ata differentrate.

v 6. Ina fluid pressure brake, the combination with a brake pipe, of means for reducing the pressure of fluid in said brakepipe at a predetermined slow. rate, and means subject to the reduced pressure` of iluid in' said brake pipe for continuing thereductionin brakepipe pressure at-a fast-er rate. 7. In a fluid pressure brake, the combination with a-brakepipe, of means for venting fluid from said brakepipe tothe `atmosphere at a predetermined rate for a period of time governedlby the length of the train, and kmeans for accelerating the rate of said reduction at the end of' said period of time.

8. In afluid pressure brake,the combination with a brake pipe, of means iorventiii T fluid from said-brake pipe to the-atmospliereat a predetermined rate fora period of time governed by the length of they train, andi means Afor additionally venting fluid from said brake pipe. to the atmosphere to accelerate the rate of said reduction at the .9. In a fluid pressure brake, the combination with a brake pipe, of-means foreffecting a reductionin brake-pipe ressure at a predetermined slow rate, an controlled'by the reduced brake" pipe pressurey for accelerating the rate of said reduction. l l

v10. Ina fluidy pressure brake, the combination with a brake' pipe and means for effecting a reduction in brake pipe pressure at ay predeterminedrate, of a valve device having a chamber normally charged with fluid vunder pressure, Vand a valve device associated .with the'first mentioned valve device and subject to the opposing pressures` of' saidchamber and the brake pipe for accelerating the rate of reductionk of the brake pipepressure. f

11. `Ina fluid pressure brake, the combination with a brake pipe and means for effecting a reduction in brake pipe pressure at a predetermined rate, of an equalizing reserioo means V1 10 voir normally charged with fluid under presf sure', means. operated lupon a vpredetermined reduction in` brake pipe pressure for effecting;- a reduction in the equalizingreservoir pressure, and means operable upon a predetermined reduction in the equalizingreservoir pressure for .accelerating the rate of reductionof the brake pipe pressure.

l2. In a fluid pressure brake, the combination with a brake pipe and means for effecting a reduction in .brake pipe pressure at a predtermined rate, of an equalizing reservoir normally `charged with fluid under pressure, means operated .upon a predetermined reduction in brake pipe pressure for effecting` a reduction in the equalizing reservoir pressure, and means `operable by the reduced brake pipe pressure upon a predetermined reduction in the equalizing reservoir pressure for accelerating the rate of reduction ofV the brake pipe pressure.

13. In a fluid pressure brake, the combina tion with brake pipe, of means for effecting a reduction` in `brake pipe pressure at a slow rate, a plurality of valve devices adapted to cooperate `with each other upon a predetermined brake pipe reduction for accelerating the rate of the brake .pipe reduction.

le. In a `fluidpressure brake, the combination with a brake pipe and an equalizing reservoir 4normally charged with Yfluid under pressure, of means for effecting a. reduction in `the pressure offluid in said brake pipe at a predetermined rate, a piston valve device operable upon a predetermined reductionin brake pipe pressure forseflecting a reduction in the equalizing reservoir precsure, valvemeans normally maintained inoperative by the fluid under equalizing res eryoir pressure and adapted to operate upon a predetermined reduction in equalizing'res- `ervoir :pressure for lfurther reducing said initializing reservoir pressure to permit the fluid-at Vthe reduced brake pipe pressure to operate said piston valve device for accel- 'eratinp` the rate of reduction of the brake pipe pressure. y

l5. In aifluid pressure brake, lthe combination `with a` brake pipe `and an equalizing` reservoir normally charged with fluid under pressure, ofmeans for effecting areiluction in thepressure of fluid in' said brake pipe at a predetermined rate, piston means operableupon a reduction in brake pipe pressure for effecting an initial reduction in the etpializing-v reservoir pressure, means operable upon said initial reduction in equaliziup; reseif'oir:pressure Vfor reducingI said equalizing` Vreservoir pressure further to a degree lower than that of the reduced brake pipe pressure to permit said piston means to be operated to accelerate the rate otreduc-V tion of the brake pipe pressure.

`16. In a fluid pressure brake, the combination with a brake pipe and an equalizing reservoir normally charged with fluid under pressure, of meansfor effecting a rekduction in the pressure of fluid in said brake pipe at a predetermined rate, piston means operable upon a reduction in brake pipe pressure for effecting an initial reduction in the equalizinp; reservoir pressure, means oper able upon said initial reductionl in equalizing reservoir pressure for reducing said equalizingreservoir pressure 'further to a degree lower than that of theredueed brake pipe pressure to permit said piston means to be operated by the fluid at reduced brake pipe pressure to aeceleate the rate of reduction of the brake pipe pressure.

17. In a fluid pressure bralre, the combination with a brake pipe and an equalizing reservoir normally charged with fluid under pressure, of means for effecting' a reduction in the pressure of fluid in said b 'alie pipe at a predetermined rate, piston means operable upon a reduction in l 1alie pipe pressure for effecting' an initial reduction in the equalizing reservoir `pressure at a rate substantially the same as tlie reduction in the brake pipeypressure, means operable upon said reduction in edualiasing` reservoir pressure for accelerating' the rate of reduction of said colualizing reservoir pressure for permitting said piston means to operate to accelerate the rate of reduc-tion of the brake pipe pressure.

18. In a. fluid pressure brake, the combination with a brake pipe and means for effecting a reductionin brake pipe pressure at a predetermined rate, of two reservoirs,

and means Voperable upon a, predetermined reduction in brake pipe pressure for venting fluid under pressure from one of said reservoirs into the other of said reservoirs to accelerate the rate of reduction in brake pipe pressure.

19. In a fluidY pressure brakdthe combination -Witli a brake pipe and means for effecting a reduction in brake pipe pressure at a predetermined rate, of two reservoirs one of. whichV is normally charged with fiuid under pressure, means operable upon a predetermined reduction in brake pipe pressure for venting fluid from the charged reservoir into the other of said reservoirs and means operable upon the ventingof said reservoir for accelerating' the rate of reduction of brake pipe pressure. p

20. In a fluid pressure brake, the combination with a brake pipe and ineens for effecting a reduction in brake pipe pressure at a predetermined rate. of tivo reservoirs one of which is normally charged with a fluid under pressure, means operable upon a predetermined reduction in brake pipe pressure for Venting fluid'fromfthe charged reservoir into the other of said reservoirs and means operable by fluid at reduced brake pipe pressure uponthe 'venting of' said reservoir for accelerating the rate of reduction of brake pipe pressure. f

normally closed to the atmosphere, one of 21. In a fluid pressure brake, the combination with a brake pipe and means for effecting a reduction in brake pipe pressure at a predetermined rate, of a piston valve device comprising a piston and a valve member loosely connected together,.said piston, upon said reduction in' brake pipe pressure, being movable relative to said valve member by fluid under pressure, 'and means for redueing the pressure of the fluid moving said piston, said piston, upon the reduction of the pressure of the fluid moving it, being movable by the reduced brake pipe pressure to operate said valve member to accelerate the rate of brake pipe reduction. l

22. Ina fluid pressure brake, the combination with a brake pipe having tivo vents which has a greater flow area than the other, a valve device operable to open the vent having the lesser flow area for venting fluid under pressure from the brake pipe t0 the` atmosphere, and Vmeans controlled by said valve device whereby a predetermined rei' duction in brake pipe pressure will cause the vent having the larger .flow area to be opened to additionally vent fluid under pressure from the brake pipe to the atmosphere.

23. In a fluid pressure brake, the combi# nation with a brake pipe having two vents normally closed to the atmosphere, one of which has a greater flow area than the other, a valve device operable to open the vent having the lesser flow area for venting fluid vunder pressure from the brake pipe to the atmosphere, and means whereby a predetermined reduction in brake pipe pressure Will cause fluid under pressure from said brake pipe to be additionally vented to the atmosphere through the other of said vents.

24. In a fluid pressure brake, the combination with a fluid supply means and a brake pipe of a control valve device having a piston chamber normally charged with fluid under pressure from said supply means, means whereby a reduction inthe pressure of the fluid in said piston chamber vWill initiate a reduction in the pressure of the fluid in said brake pipe, means for restricting said brake pipe reduction to a slovv rate, and means operable upon a predetermined reduction in brake pipe pressure for accelerating the rate of said reduction in brake pipe pressure.

25. In a fluid pressure brake, the combination With a brake pipe, of a control valve' device normally charged with fluid under pressure and operable upon a reduction in said pressure for initiating a reduction in the pressure of fluid in said brake pipe at a restricted rate, and means for accelerating the rateo'f reduction in the brake pipe pressure when said brake pipe pressure has been reduced to a predetermined degree.

26. In a fluid pressure brake, the method of effecting a continuous reduction in brake leading to the atmosphere for a period of time governedV by the length of the train,

and then automatically reducing the brake pipe pressure at a different rate.

28. In a fluid pressure brake, the method of effecting a continuous reduction in brake pipe pressure consisting in first automatically reducing the pressure of fluid in a control valve device causing said device to operate to vent said brake pipe tothe atmosphere through a restricted passage and then after a period of time permitting the fluid at reduced brake pipe pressure to operate means to additionally vent said brake rpipe,

to the atmosphere.

29. In a fluid pressure brake, .the combina-y tion with a brake pipe and a normally charged reservoir, of means for initially venting fluid from the brake pipe at a predetermined rate, means operated upon a predetermined reduction in pressure in said reservoir for also effecting a venting of fluid A from the brake pipe, and means for reducing the pressure in said reservoir.

30. `In a fluid pressure brake, the combina# tion with a brake ipe and a normally charged reservoir, of) means for initially venting fluid from the brake pipe at a predetermined rate, means operated upon a predetermined reduction in pressure in said reservoir for also effecting a venting of fluid from the brake pipe, and means for reducing the pressure in said reservoir at a rate substantially proportional to the rate at which theV brake pipe pressure is initally reduced.

31. In a fluid pressure brake, the combination with a brake pipe and a normally charged reservoir, of means for initially venting fluid from the brake pipe at a predetermined rate, means operated upon a predetermined reduction in pressure in said reservoir for also effecting a venting of fluid from the brake pipe', and means operated upon initially reducing the brake pipe pres-` my hand.

.THOMAS H. THOMAS.r 

